蛇床子素对离体豚鼠心房的作用(英文)

Effects of osthole on isolated guinea pig heart atria

目的:研究蛇床子素对离体豚鼠心房的作用及与Ca^(2+)的关系.方法:钙拮抗剂Ver对照,电刺激左房收缩,累积浓度法测定给Ost前后左房收缩幅度,给药间隔15 min,计算pA_2或pD_2′;观察Ost对左房收缩正阶梯、静息后增强作用。收缩反应由XWT-204台式平衡记录仪描记.结果:Ost、Ver产生浓度依赖性负性肌力作用,抑制高K^+Iso恢复的左房收缩;非竞争性拮抗Iso、CaCl_2正性肌力作用,相应pD_2′值分别为4.41±0.13和6.53±0.22,4.90±0.15和6.91±0.17;抑制正阶梯,大剂量使之翻转,对静息后增强作用弱.结论:Ost对心房抑制作用与Ver相似,但强度较后者弱,可能抑制胞外钙内流.

AIM: To study the effects of osthole (Ost) on the isolated guinea pig atria and the relationship between Ost effect and Ca2+ METHODS: Contractions of left atria were induced by electric stimulations. The contractile amplitude of left atria pre- and post-treated with Ost was measured according to the cumulative concentration method, the drug being added at 15 min intervals, the pA2 or pD2' were calculated. It were measured that the effects of Ost to the positive staircase and to the post-rest potential enhancement. The contractile responses were recorded via an auto-equiolibration recording instrument. RESULTS: Ost 10-300umol·L-1 and Ver 0. 1 - 30μmol·L-1 decreased the contractile force and inhibited the isoprenaline-induced restoration of contractile response in the left atria rendered inexcitable by KC1 25 mmol·L-1. Ost and Ver antagonized the CaCl2-and isoprenaline-induced positive inotropic response noncompetively, the pD2' values to Ost were 4. 41±0. 13 and 4. 90±0. 15, to Ver were 6. 53±0. 22 and 6. 91±0. 17, respectively. Both of them inhibited the contraction of the left atrium and reversed the frequency-contraction response from positive to negative staircase in the higher dosage (500 and 1μmol·L-1), but they showed only slight inhibitory effect on post-rest potentiation. CONCLUSION : Ost was similar to, but much less . potent than Ver in inhibiting the isolated guinea pig atria.